The ISO is less than 100MB and there are versions for both Intel and ARM-based platforms and I set mine up on nothing fancy (a HP Compaq 8200 ultra-slim desktop with Core i3 and 8GB RAM). It took around 30 minutes to have running the current CE version of docker, together with a ubuntu console (more of which, later).

So, the idea is to boot off the ISO, install to hard drive and then access remotely via ssh – so I can hide the ancient HP box under my desk.

First, create a config file containing the public part of an ssh-key, something similar to this, taking care to indent the 2nd line

A word of caution – this didn’t work for me the first couple of times I tried it; the problem was the layout of the .yml file. Rancher must have seen this before, because they provide a yml file validator.
So, pull the .yml file to your local shell with:

wget http://[your-server-IP]:8000/cloud-config.yml

and run

sudo ros config validate -i cloud-config.yml

OK, so run the install command as above, answer yes when asked and Rancher OS will be installed to your hard drive.

Congratulations! You now have the bare minimum of OS on which to run your docker containers.

But wait – Rancher OS can be made even more useful by swapping out the default busybox console: